Method for edge sealing barrier films

ABSTRACT

An edge-sealed barrier film composite. The composite includes a substrate and at least one initial barrier stack adjacent to the substrate. The at least one initial barrier stack includes at least one decoupling layer and at least one barrier layer. One of the barrier layers has an area greater than the area of one of the decoupling layers. The decoupling layer is sealed by the first barrier layer within the area of barrier material. An edge-sealed, encapsulated environmentally sensitive device is provided. A method of making the edge-sealed barrier film composite is also provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a division of U.S. patent application Ser. No.11/068,356, filed Feb. 28, 2005, and entitled “METHOD FOR EDGE SEALINGBARRIER FILMS”, which is a division of U.S. patent application Ser. No.09/966,163, filed Sep. 28, 2001, and entitled “METHOD FOR EDGE SEALINGBARRIER FILMS” now U.S. Pat. No. 6,866,901, issued Mar. 15, 2005 whichis a continuation-in-part of U.S. patent application Ser. No.09/427,138, filed Oct. 25, 1999, entitled “ENVIRONMENTAL BARRIERMATERIAL FOR ORGANIC LIGHT EMITTING DEVICE AND METHOD OF MAKING,” nowU.S. Pat. No. 6,522,067, issued Feb. 18, 2003.

BACKGROUND OF THE INVENTION

The invention relates generally to multilayer, thin film barriercomposites, and more particularly, to multilayer, thin film barriercomposites having the edges sealed against lateral moisture and gasdiffusion.

Multilayer, thin film barrier composites having alternating layers ofbarrier material and polymer material are known. These composites aretypically formed by depositing alternating layers of barrier materialand polymer material, such as by vapor deposition. If the polymer layersare deposited over the entire surface of the substrate, then the edgesof the polymer layers are exposed to oxygen, moisture, and othercontaminants. This potentially allows the moisture, oxygen, or othercontaminants to diffuse laterally into an encapsulated environmentallysensitive device from the edge of the composite, as shown in FIG. 1. Themultilayer, thin film barrier composite 100 includes a substrate 105 andalternating layers of decoupling material 110 and barrier material 115.The scale of FIG. 1 is greatly expanded in the vertical direction. Thearea of the substrate 105 will typically vary from a few squarecentimeters to several square meters. The barrier layers 115 aretypically a few hundred Angstroms thick, while the decoupling layers 110are generally less than ten microns thick. The lateral diffusion rate ofmoisture and oxygen is finite, and this will eventually compromise theencapsulation. One way to reduce the problem of edge diffusion is toprovide long edge diffusion paths. However, this decreases the area ofthe substrate which is usable for active environmentally sensitivedevices. In addition, it only lessens the problem, but does noteliminate it.

A similar edge diffusion problem will arise when a substrate containinga multilayer, thin film barrier composite is scribed and separated tocreate individual components.

Thus, there is a need for a edge-sealed barrier film composite, and fora method of making such a composite.

SUMMARY OF THE INVENTION

The present invention solves this need by providing an edge-sealedbarrier film composite. The composite comprises a substrate, and atleast one initial barrier stack adjacent to the substrate, the at leastone initial barrier stack comprising at least one decoupling layer andat least one barrier layer, wherein a first decoupling layer has an areaand wherein a first barrier layer has an area, the area of the firstbarrier layer being greater than the area of the first decoupling layer,and wherein the first decoupling layer is sealed by the first barrierlayer within the area of the first barrier layer. By adjacent, we meannext to, but not necessarily directly next to. There can be additionallayers intervening between the substrate and the barrier stacks.

The first layer can be either a decoupling layer or a barrier layer, ascan the last layer. One or more barrier stacks can include at least twodecoupling layers and/or at least two barrier layers. When a barrierstack has at least two barrier layers, a second barrier layer may havean area greater than the area of the first decoupling layer, and thefirst and second barrier layers may seal the first decoupling layerbetween them.

The decoupling layers can be made from materials including, but notlimited to, organic polymers, inorganic polymers, organometallicpolymers, hybrid organic/inorganic polymer systems, silicates, andcombinations thereof. The decoupling layers can be made of the samedecoupling material or different decoupling materials.

Suitable barrier materials include, but are not limited to, metals,metal oxides, metal nitrides, metal carbides, metal oxynitrides, metaloxyborides, and combinations thereof. Suitable barrier materials alsoinclude, but are not limited to, opaque metals, opaque ceramics, opaquepolymers, and opaque cermets, and combinations thereof. The barrierlayers can be made of the same barrier material or different barriermaterial.

The composite can include an environmentally sensitive device.Environmentally sensitive devices include, but are not limited to,organic light emitting devices, liquid crystal displays, displays usingelectrophoretic inks, light emitting diodes, light emitting polymers,electroluminescent devices, phosphorescent devices, electrophoreticinks, organic solar cells, inorganic solar cells, thin film batteries,and thin film devices with vias, and combinations thereof.

Another aspect of the invention is an edge-sealed, encapsulatedenvironmentally sensitive device. The edge-sealed, encapsulatedenvironmentally sensitive device includes: at least one initial barrierstack comprising at least one decoupling layer and at least one barrierlayer, wherein a first decoupling layer of a first initial barrier stackhas an area and wherein a first barrier layer of the first initialbarrier stack has an area, the area of the first barrier layer of thefirst initial barrier stack being greater than the area of the firstdecoupling layer of the first initial barrier stack, and wherein thefirst decoupling layer of the first initial barrier stack is sealed bythe first barrier layer of the first initial barrier stack within thearea of the first barrier layer; an environmentally sensitive deviceadjacent to the at least one initial barrier stack; and at least oneadditional barrier stack adjacent to the environmentally sensitivedevice on a side opposite the at least one initial barrier stack, the atleast one additional barrier stack comprising at least one decouplinglayer and at least one barrier layer, wherein a first decoupling layerof a first additional barrier stack has an area and wherein a firstbarrier layer of the first additional barrier stack has an area, thearea of the first barrier layer of the first additional barrier stackbeing greater than the area of the first decoupling layer of the firstadditional barrier stack, wherein the first decoupling layer of thefirst additional barrier stack is sealed by the first barrier layer ofthe first additional barrier stack within the area of the first barrierlayer, and wherein the environmentally sensitive device is sealedbetween the at least one initial barrier stack and the at least oneadditional barrier stack.

Another aspect of the invention is a method of making an edge-sealedbarrier film composite. The method includes providing a substrate, andplacing at least one initial barrier stack adjacent to the substrate,the at least one initial barrier stack comprising at least onedecoupling layer and at least one barrier layer, wherein a firstdecoupling layer of a first initial barrier stack has an area andwherein a first barrier layer of the first initial barrier stack has anarea, the area of the first barrier layer being greater than the area ofthe first decoupling layer, and wherein the first decoupling layer issealed by the first barrier layer within the area of the first barrierlayer.

Placing the at least one barrier stack adjacent to the substrateincludes, but is not limited to, depositing the at least one barrierstack adjacent to the substrate, and laminating the at least one barrierstack adjacent to the substrate.

The barrier layers can be deposited before or after the decouplinglayers, depending on the particular application and structure.

Depositing the at least one barrier stack may include, but is notlimited to, providing a mask with at least one opening, depositing thefirst decoupling layer through the at least one opening in the mask, anddepositing the first barrier layer.

Alternatively, depositing the at least one barrier stack adjacent to thesubstrate may include, but is not limited to, depositing the firstdecoupling layer having an initial area of decoupling material which isgreater than the area of the first decoupling layer, etching the firstdecoupling layer having the initial area of decoupling material toremove a portion of the decoupling material so that the first decouplinglayer has the area of the first decoupling layer, and depositing thefirst barrier layer. Etching the first decoupling layer may include, butis not limited to, providing a solid mask over the first decouplinglayer having the initial area of decoupling material, and etching thefirst decoupling layer having the initial area of decoupling material toremove the portion of the decoupling material outside the solid mask sothat the first decoupling layer has the area of the first decouplinglayer. The first decoupling layer may be etched so that at least oneedge of the first decoupling layer has a gradual slope. A reactiveplasma may be used to etch the decoupling layers. Reactive plasmasinclude, but are not limited to O₂, CF₄, H₂, and combinations thereof.

The method may include placing an environmentally sensitive deviceadjacent to the substrate before the at least one initial barrier stackis placed thereon. Alternatively, the method may include placing theenvironmentally sensitive device adjacent to the at least one initialbarrier stack after the at least one initial barrier stack is placed onthe substrate. The method may also include placing at least oneadditional barrier stack adjacent to the environmentally sensitivedevice on a side opposite the substrate, the at least one additionalbarrier stack comprising at least one decoupling layer and at least onebarrier layer, wherein a first decoupling layer of a first additionalbarrier stack has an area and wherein a first barrier layer of the firstadditional barrier stack has an area, the area of the first barrierlayer of the first additional barrier stack being greater than the areaof the first decoupling layer of the first additional barrier stack, andwherein the first decoupling layer of the first additional barrier stackis sealed by the first barrier layer of the first additional barrierstack within the area of the first barrier layer.

Laminating the at least one barrier stack adjacent to the substrate maybe performed using a number of processes including, but not limited to,heat, solder, adhesive, ultrasonic welding, and pressure.

The method may include depositing a ridge on the substrate beforedepositing the at least one barrier stack adjacent to the substrate, theridge interfering with the deposition of the first decoupling layer sothat the area of the first barrier layer is greater than the area of thefirst decoupling layer and the first decoupling layer is sealed by thefirst barrier layer within the area of the first barrier layer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-section of a barrier composite of the prior art.

FIG. 2 is a cross-section of one embodiment of an edge-sealed, barriercomposite of the present invention.

FIG. 3 is a cross-section of an embodiment of an edge-sealed,encapsulated environmentally sensitive device of the present invention.

FIG. 4 is a cross-section of a second embodiment of an edge-sealed,encapsulated environmentally sensitive device of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 2 shows one embodiment of an edge-sealed, barrier composite 200.The composite 200 includes a substrate 205. The substrate can be anysuitable substrate, and can be either rigid or flexible. Suitablesubstrates include, but are not limited to: polymers, for example,polyethylene terephthalate (PET), polyethylene naphthalate (PEN), orhigh temperature polymers, such as polyether sulfone (PES), polyimides,or Transphan™ (a high glass transition temperature cyclic olefin polymeravailable from Lofo High Tech Film, GMBH of Weil am Rhein, Germany);metals and metal foils; paper; fabric; glass, including thin, flexible,glass sheet (for example, flexible glass sheet available from CorningInc. under the glass code 0211. This particular thin, flexible glasssheet has a thickness of less than 0.6 mm and will bend at a radium ofabout 8 inches.); ceramics; semiconductors; silicon; and combinationsthereof.

FIG. 2 shows three initial barrier stacks 220 adjacent to the substrate205. The initial barrier stacks 220 include a decoupling layer 210 and abarrier layer 215. The barrier layer 215 has an area greater than thearea of the decoupling layer 210. As a result, the barrier layer 215extends beyond the edges of the decoupling layer 210, sealing thedecoupling layer 210 within the area covered by the barrier layer 215.Because the decoupling layers 210 are sealed within the area covered bythe barrier layers 215, ambient moisture, oxygen, and other contaminantscannot diffuse through the decoupling layers to the environmentallysensitive device.

FIG. 2 shows three initial barrier stacks 220. However, the number ofbarrier stacks is not limited. The number of barrier stacks neededdepends on the substrate material used and the level of permeationresistance needed for the particular application. One or two barrierstacks may provide sufficient barrier properties for some applications.The most stringent applications may require five or more barrier stacks.

Each of the initial barrier stacks 220 shown in FIG. 2 has one barrierlayer 215 and one decoupling layer 210. However, the barrier stacks canhave one or more decoupling layers and one or more barrier layers. Therecould be one decoupling layer and one barrier layer, there could be oneor more decoupling layers on one side of one or more barrier layers,there could be one or more decoupling layers on both sides of one ormore barrier layers, or there could be one or more barrier layers onboth sides of one or more decoupling layers. The important feature isthat the barrier stack have at least one decoupling layer and at leastone barrier layer. The barrier layers in the barrier stacks can be madeof the same material or of a different material, as can the decouplinglayers. The barrier layers are typically about 100-400 Å thick, and thedecoupling layers are typically about 1000-10,000 Å thick.

Although the three initial barrier stacks 220 are shown as having thesame layers in the same order, this is not necessary. The barrier stackscan have the same or different layers, and the layers can be in the sameor different sequences.

If there is only one barrier stack and it has only one decoupling layerand one barrier layer, then the decoupling layer must be first in orderfor the barrier layer to seal it, as shown in FIG. 2. The decouplinglayer will be sealed between the substrate (or the upper layer of theprevious barrier stack) and the barrier layer. Although a composite canbe made with a single barrier stack having one decoupling layer and onebarrier layer, there will typically be at least two barrier stacks, eachhaving one (or more) decoupling layer and one (or more) barrier layer.In this case, the first layer can be either a decoupling layer or abarrier layer, as can the last layer.

FIG. 3 shows an edge-sealed, encapsulated environmentally sensitivedevice 300. There is a substrate 305 with an environmentally sensitivedevice 330 adjacent to it. There is a barrier stack 340 adjacent to theenvironmentally sensitive device 330. The barrier stack includes onedecoupling layer 310 and two barrier layers 315, 325. The barrier layer315 has an area greater than that of the environmentally sensitivedevice 330. Thus, the environmentally sensitive device 330 is sealedwithin the barrier layer 315. The barrier layers 315, 325 have an areagreater than the area of the decoupling layer 310 so the decouplinglayer 310 is sealed between the barrier layers 315, 325.

The environmentally sensitive device can be any device requiringprotection from moisture, gas, or other contaminants. Environmentallysensitive devices include, but are not limited to, organic lightemitting devices, liquid crystal displays, displays usingelectrophoretic inks, light emitting diodes, light emitting polymers,electroluminescent devices, phosphorescent devices, electrophoreticinks, organic solar cells, inorganic solar cells, thin film batteries,and thin film devices with vias, and combinations thereof.

It is not required that all of the barrier layers have an area greaterthan all of the decoupling layers, but at least one of the barrierlayers must have an area greater than at least one of the decouplinglayers. If not all of the barrier layers have an area greater than ofthe decoupling layers, the barrier layers which do have an area greaterthan the decoupling layers should form a seal around those which do notso that there are no exposed decoupling layers within the barriercomposite, although, clearly it is a matter of degree. The fewer theedge areas of decoupling layers exposed, the less the edge diffusion. Ifsome diffusion is acceptable, then a complete barrier is not required.

FIG. 4 shows an edge-sealed, encapsulated environmentally sensitivedevice 400. There is a substrate 405 which can be removed after thedevice is made, if desired. The environmentally sensitive device 430 isencapsulated between two initial barrier stacks 420, 422 on one side andone additional barrier stack 440 on the other side.

Barrier stack 420 has a barrier layer 415 which has an area greater thanthe area of the decoupling layer 410 which seals the decoupling layer410 within the area of the barrier layer 415. Barrier stack 422 has twobarrier layers 415, 417 and two decoupling layers 410, 412. Barrierlayer 415 has an area greater than that of the decoupling layers 410,412 which seals the decoupling layers 410, 412 within the area of thebarrier layer 415. There is a second barrier layer 417.

On the other side of the environmentally sensitive device 430, there isan additional barrier stack 440. Barrier stack 440 includes twodecoupling layers 410 and two barrier layers 415 which may be ofapproximately the same size. Barrier stack 440 also includes barrierlayer 435 which has an area greater than the area of the decouplinglayers 410 which seals the decoupling layers 410 within the area ofbarrier layer 435.

The barrier layer which seals the decoupling layer may be the firstbarrier layer in the barrier stack, as shown in barrier stack 420. Itmay also be a second (or later) barrier layer as shown in barrier stack440. Barrier layer 435 which seals the barrier stack 440 is the thirdbarrier layer in the barrier stack following two barrier layers 415which do not seal the barrier stack. Thus, the use of the terms firstdecoupling layer and first barrier layer in the claims does not refer tothe actual sequence of layers, but to layers which meet the limitations.Similarly, the terms first initial barrier stack and first additionalbarrier stack do not refer to the actual sequence of the initial andadditional barrier stacks.

The barrier stack may include one or more decoupling layers. Thedecoupling layers may be made from the same decoupling material ordifferent decoupling material. The decoupling layer can be made of anysuitable decoupling material, including, but not limited to, organicpolymers, inorganic polymers, organometallic polymers, hybridorganic/inorganic polymer systems, silicates, and combinations thereof.Organic polymers include, but are not limited to, urethanes, polyamides,polyimides, polybutylenes, isobutylene isoprene, polyolefins, epoxies,parylenes, benzocyclobutadiene, polynorbornenes, polyarylethers,polycarbonates, alkyds, polyaniline, ethylene vinyl acetate, ethyleneacrylic acid, and combinations thereof. Inorganic polymers include, butare not limited to, silicones, polyphosphazenes, polysilazanes,polycarbosilanes, polycarboranes, carborane siloxanes, polysilanes,phosphonitriles, sulfur nitride polymers, siloxanes, and combinationsthereof. Organometallic polymers include, but are not limited to,organometallic polymers of main group metals, transition metals, andlanthanide/actinide metals, or combinations thereof. Hybridorganic/inorganic polymer systems include, but are not limited to,organically modified silicates, preceramic polymers, polyimide-silicahybrids, (meth)acrylate-silica hybrids, polydimethylsiloxane-silicahybrids, ceramers, and combinations thereof.

The barrier stack may include one or more barrier layers. The barrierlayers may be made from the same barrier material or different barriermaterial. The barrier layer can be made from any suitable barriermaterial. The barrier material can be transparent or opaque depending onwhat the composite is to be used for. Suitable barrier materialsinclude, but are not limited to, metals, metal oxides, metal nitrides,metal carbides, metal oxynitrides, metal oxyborides, and combinationsthereof. Metals include, but are not limited to, aluminum, titanium,indium, tin, tantalum, zirconium, niobium, hafnium, yttrium, nickel,tungsten, chromium, zinc, alloys thereof, and combinations thereof.Metal oxides include, but are not limited to, silicon oxide, aluminumoxide, titanium oxide, indium oxide, tin oxide, indium tin oxide,tantalum oxide, zirconium oxide, niobium oxide, hafnium oxide, yttriumoxide, nickel oxide, tungsten oxide, chromium oxide, zinc oxide, andcombinations thereof. Metal nitrides include, but are not limited to,aluminum nitride, silicon nitride, boron nitride, germanium nitride,chromium nitride, nickel nitride, and combinations thereof. Metalcarbides include, but are not limited to, boron carbide, tungstencarbide, silicon carbide, and combinations thereof. Metal oxynitridesinclude, but are not limited to, aluminum oxynitride, siliconoxynitride, boron oxynitride, and combinations thereof. Metal oxyboridesinclude, but are limited to, zirconium oxyboride, titanium oxyboride,and combinations thereof. Suitable barrier materials also include, butare not limited to, opaque metals, opaque ceramics, opaque polymers, andopaque cermets, and combinations thereof. Opaque cermets include, butare not limited to, zirconium nitride, titanium nitride, hafniumnitride, tantalum nitride, niobium nitride, tungsten disilicide,titanium diboride, and zirconium diboride, and combinations thereof.

The barrier layers may be deposited by any suitable process including,but not limited to, conventional vacuum processes such as sputtering,evaporation, sublimation, chemical vapor deposition (CVD), plasmaenhanced chemical vapor deposition (PECVD), electron cyclotronresonance-plasma enhanced vapor deposition (ECR-PECVD), and combinationsthereof.

The decoupling layer can be produced by a number of known processeswhich provide improved surface planarity, including both atmosphericprocesses and vacuum processes. The decoupling layer may be formed bydepositing a layer of liquid and subsequently processing the layer ofliquid into a solid film. Depositing the decoupling layer as a liquidallows the liquid to flow over the defects in the substrate or previouslayer, filling in low areas, and covering up high points, providing asurface with significantly improved planarity. When the decoupling layeris processed into a solid film, the improved surface planarity isretained. Suitable processes for depositing a layer of liquid materialand processing it into a solid film include, but are not limited to,vacuum processes such as those described in U.S. Pat. Nos. 5,260,095,5,395,644, 5,547,508, 5,691,615, 5,902,641, 5,440,446, and 5,725,909,which are incorporated herein by reference, and atmospheric processessuch as spin coating and/or spraying.

One way to make a decoupling layer involves depositing a polymerprecursor, such as a (meth)acrylate containing polymer precursor, andthen polymerizing it in situ to form the decoupling layer. As usedherein, the term polymer precursor means a material which can bepolymerized to form a polymer, including, but not limited to, monomers,oligomers, and resins. As another example of a method of making adecoupling layer, a preceramic precursor could be deposited as a liquidby spin coating and then converted to a solid layer. Full thermalconversion is possible for a film of this type directly on a glass oroxide coated substrate. Although it cannot be fully converted to aceramic at temperatures compatible with some flexible substrates,partial conversion to a cross-lined network structure would besatisfactory. Electron beam techniques could be used to crosslink and/ordensify some of these types of polymers and can be combined with thermaltechniques to overcome some of the substrate thermal limitations,provided the substrate can handle the electron beam exposure. Anotherexample of making a decoupling layer involves depositing a material,such as a polymer precursor, as a liquid at a temperature above itsmelting point and subsequently freezing it in place.

One method of making the composite of the present invention includesproviding a substrate, and depositing a barrier layer adjacent to thesubstrate at a barrier deposition station. The substrate with thebarrier layer is moved to a decoupling material deposition station. Amask is provided with an opening which limits the deposition of thedecoupling layer to an area which is smaller than, and contained within,the area covered by the barrier layer. The first layer deposited couldbe either the barrier layer or the decoupling layer, depending on thedesign of the composite.

In order to encapsulate multiple small environmentally sensitive devicescontained on a single large motherglass, the decoupling material may bedeposited through multiple openings in a single shadow mask, or throughmultiple shadow masks. This allows the motherglass to be subsequentlydiced into individual environmentally sensitive devices, each of whichis edge sealed.

For example, the mask may be in the form of a rectangle with the centerremoved (like a picture frame). The decoupling material is thendeposited through the opening in the mask. The layer of decouplingmaterial formed in this way will cover an area less than the areacovered by the layer of barrier material. This type of mask can be usedin either a batch process or a roll coating process operated in a stepand repeat mode. With these processes, all four edges of the decouplinglayer will be sealed by the barrier material when a second barrier layerwhich has an area greater than the area of the decoupling layer isdeposited over the decoupling layer.

The method can also be used in a continuous roll to roll process using amask having two sides which extend inward over the substrate. Theopening is formed between the two sides of the mask which allowscontinuous deposition of decoupling material. The mask may havetransverse connections between the two sides so long as they are not inthe deposition area for the decoupling layer. The mask is positionedlaterally and at a distance from the substrate so as to cause thedecoupling material to be deposited over an area less than that of thebarrier layer. In this arrangement, the lateral edges of the decouplinglayer are sealed by the barrier layer.

The substrate can then be moved to a barrier deposition station (eitherthe original barrier deposition station or a second one), and a secondlayer of barrier material deposited on the decoupling layer. Since thearea covered by the first barrier layer is greater than the area of thedecoupling layer, the decoupling layer is sealed between the two barrierlayers. These deposition steps can be repeated if necessary untilsufficient barrier material is deposited for the particular application.

When one of the barrier stacks includes two or more decoupling layers,the substrate can be passed by one or more decoupling materialdeposition stations one or more times before being moved to the barrierdeposition station. The decoupling layers can be made from the samedecoupling material or different decoupling material. The decouplinglayers can be deposited using the same process or using differentprocesses.

Similarly, one or more barrier stacks can include two or more barrierlayers. The barrier layers can be formed by passing the substrate(either before or after the decoupling layers have been deposited) pastone or more barrier deposition stations one or more times, building upthe number of layers desired. The layers can be made of the same ordifferent barrier material, and they can be deposited using the same ordifferent processes.

In another embodiment, the method involves providing a substrate anddepositing a layer of barrier material on the surface of the substrateat a barrier deposition station. The substrate with the barrier layer ismoved to a decoupling material deposition station where a layer ofdecoupling material is deposited over substantially the whole surface ofthe barrier layer. A solid mask is then placed over the substrate withthe barrier layer and the decoupling layer. The mask protects thecentral area of the surface, which would include the areas covered bythe active environmentally sensitive devices. A reactive plasma can beused to etch away the edges of the layer of decoupling material outsidethe mask, which results in the layer of etched decoupling materialcovering an area less than the area covered by the layer of barriermaterial. Suitable reactive plasmas include, but are not limited to, O₂,CF₄, and H₂, and combinations thereof. A layer of barrier materialcovering an area greater than that covered by the etched decouplinglayer can then be deposited, sealing the etched decoupling layer betweenthe layers of barrier material.

To ensure good coverage of the edge of the decoupling layer by thebarrier layer, techniques for masking and etching the decoupling layerto produce a feathered edge, i.e., a gradual slope instead of a sharpstep, may be employed. Several such techniques are known to those in theart, including, but not limited to, standing off the mask a shortdistance above a polymer surface to be etched.

The deposition and etching steps can be repeated until sufficientbarrier material is deposited. This method can be used in a batchprocess or in a roll coating process operated in a step and repeat mode.In these processes, all four edges of the decoupling layer may beetched. This method can also be used in continuous roll to rollprocesses. In this case, only the edges of the decoupling material inthe direction of the process are etched.

If a composite is made using a continuous process and the edged sealedcomposite is cut in the transverse direction, the cut edges will exposethe edges of the decoupling layers. These cut edges may requireadditional sealing if the exposure compromises barrier performance.

One method for sealing edges which are to be cut involves depositing aridge on the substrate before depositing the barrier stack. The ridgeinterferes with the deposition of the decoupling layer so that the areaof barrier material is greater than the area of decoupling material andthe decoupling layer is sealed by the barrier layer within the area ofbarrier material. The ridge should be fairly pointed, for example,triangular shaped, in order to interrupt the deposition and allow thelayers of barrier material to extend beyond the layers of decouplingmaterial. The ridge can be deposited anywhere that a cut will need to bemade, such as around individual environmentally sensitive devices. Theridge can be made of any suitable material, including, but not limitedto, photoresist and barrier materials, such as described previously.

While certain representative embodiments and details have been shown forpurposes of illustrating the invention, it will be apparent to thoseskilled in the art that various changes in the compositions and methodsdisclosed herein may be made without departing from the scope of theinvention, which is defined in the appended claims.

1. A method of making an edge-sealed barrier film composite, the methodcomprising: providing a substrate consisting essentially of a polymer;and depositing at least one initial barrier stack directly on thesubstrate, the at least one initial barrier stack comprising at leastone decoupling layer comprising an organic material and at least twobarrier layers comprising an inorganic material such that a first layerof the at least two barrier layers is deposited directly on thesubstrate, wherein the at least one decoupling layer defines an area andwherein the first layer of the at least two barrier layers has an areathat is greater than the area of the at least one decoupling layer suchthat the at least one decoupling layer is sealed from the substrate byat least the first layer of the at least two barrier layers.
 2. Themethod of claim 1, wherein a second layer of the at least two barrierlayers has an area greater than the area of the at least one decouplinglayer and wherein the first and second layers of the at least twobarrier layers seal the at least one decoupling layer between them. 3.The method of claim 1, wherein the at least one initial barrier stackcomprises two barrier stacks such that a first barrier layer of thesecond barrier stack is deposited directly on a top layer of the firstbarrier stack.
 4. The method of claim 1, wherein depositing the at leastone initial barrier stack directly on the substrate comprises: providingat least one mask with at least one opening; and depositing the firstlayer of the at least two barrier layers and the at least one decouplinglayer through the at least one opening in the at least one mask.
 5. Themethod of claim 4, wherein the at least one decoupling layer is etchedso that at least one edge of the at least one decoupling layer has agradual slope.
 6. The method of claim 5, wherein the at least onedecoupling layer is etched using a reactive plasma.
 7. The method ofclaim 6, wherein the reactive plasma is selected from O₂, CF₄, H₂ orcombinations thereof.
 8. The method of claim 1, wherein at least onedecoupling layer comprises at least two decoupling layers.
 9. The methodof claim 1, further comprising placing an environmentally sensitivedevice adjacent to the substrate before the at least one initial barrierstack is placed thereon.
 10. The method of claim 1, further comprisingplacing an environmentally sensitive device adjacent to the at least oneinitial barrier stack after the at least one initial barrier stack isplaced on the substrate.
 11. The method of claim 10, further comprisingplacing at least one additional barrier stack adjacent to theenvironmentally sensitive device on a side opposite the substrate, theat least one additional barrier stack comprising at least one decouplinglayer and at least one barrier layer, wherein a first decoupling layerof a first additional barrier stack has an area and wherein a firstbarrier layer of the first additional barrier stack has an area, thearea of the first barrier layer of the first additional barrier stackbeing greater than the area of the first decoupling layer of the firstadditional barrier stack, and wherein the first decoupling layer of thefirst additional barrier stack is sealed by the first barrier layer ofthe first additional barrier stack within the area of the first barrierlayer.
 12. The method of claim 1, further comprising depositing a ridgeon the substrate before depositing the at least one initial barrierstack adjacent to the substrate, the ridge interfering with thedeposition of the first decoupling layer so that the area of the firstbarrier layer is greater than the area of the first decoupling layer.13. The method of claim 1, wherein placing the at least one initialbarrier stack adjacent to the substrate comprises laminating the atleast one initial barrier stack adjacent to the substrate.
 14. Themethod of claim 13, wherein the at least one initial barrier stack islaminated adjacent to the substrate using a process selected fromheating, soldering, using an adhesive, ultrasonic welding and applyingpressure.